Metal amides are useful as precursor compounds for chemical vapor deposition; see, e.g., U.S. Pat. Nos. 5,178,911; 5,417,823, and 6,080,446, Metal amides are also useful in the synthesis of polymerization catalysts; see, e.g., U.S. Pat. No. 6,020,444. Metal amides are also useful in formation of metal-rich layers or materials having high dielectric constants, such as are used, in construction of microelectronic devices; see, e.g., WO 02/27063. Metal imido compounds are useful as Zieglar-Natta olefin metathesis polymerization catalysts; see, e.g., U.S. Pat. No. 5,405,924.
Many known processes for making metal amides and/or metal imidos require the transfer of a solid transition metal salt to a slurry of a lithium alkylamide. See, e.g., D. C. Bradley and I. M. Thomas, J. Chem. Soc., 1960, 3857-3861. The addition of solids into a reaction vessel with a reactive reagent present is a difficult and potentially hazardous operation on commercial scale since the flow is hard to control. The reverse reaction (i.e., adding a lithium amide to a metal halide slurry) is also possible, however the lithium amide salts are usually of low solubility and slurries of these salts tend to be nonhomogeneous, thick and difficult to completely transfer, and thus reaction stoichiometry cannot he adequately controlled to provide metal amides and imidos of commercially acceptable quality and quantity. The reverse addition also requires the use of a second vessel for processing and is therefore less desirable.
U.S. Pat. No. 7,238,821 discloses a method tor making large scale organometallic compounds, including transition metal amides, via a one-pot process wherein (i) a hydrocarbon or hetereatom-containing material, such as an amine, is reacted with a base material, such as butyl-lithium, in the presence of a solvent, to produce a first reaction mixture, (ii) a metal source is added to the first reaction mixture, (iii) the hydrocarbon or heteroatom-containing material is reacted with the metal source to produce a second reaction mixture comprising the organometallic compound, and (iv) the organometallic compound is separated from the second reaction mixture. In the reference D. C. Bradley and I. M. Thomas, J. Chem. Soc, 1960, 3857-3861, the same process is disclosed at page 3860 wherein, butyllithium, produced from n-butyl bromide and lithium, and diethylamide are combined form a first reaction mixture, to which a metal compound and solvent are added. The first reaction mixture is caused to react such that a second reaction mixture is formed comprising a metal amide, which is subsequently separated from the second reaction mixture.
Despite advancements in the synthesis of metal amides and imidos, there is a continuing need to develop more efficient and lower cost processes.